gpt-5.1-chat Preview

Historical specifications. - Reasoning - Chat Completions API. - Responses API . - Structured outputs - Functions, tools, and parallel tool calling.

Context
128K
Max output
16K

Capabilities

Reasoning & Interaction
Reasoning
Tool Calling
Output Control
Structured Output
JSON Mode
Infrastructure
Streaming

Details

Model IDgpt-5.1-chat
Provider Azure AI Foundry
Creator OpenAI
Familygpt-5.1
License—
Status—
Typechat
Input modalitiestext
Output modalitiestext
Open weight—
Parameters—
Architecture—
Context window128K tokens
Max input—
Max output16K tokens
Reasoning tokens—
Knowledge cutoff
Release date—
Sourceofficial

Tools

Function Callingfunction_calling
Call external functions and APIs

Family Comparison: gpt-5.1

ModelContextMax out
gpt-5.1-chat Preview128K16K
gpt-5.1-codex-max400K128K
gpt-5.1-codex-mini400K128K
gpt-5.1-codex400K128K
GPT-5.1 series400K128K

API

GET/v1/models/azure/gpt-5.1-chat

gpt-5.1-chat Preview

gpt-5.1-chat

Historical specifications. - Reasoning - Chat Completions API. - Responses API . - Structured outputs - Functions, tools, and parallel tool calling.

Changes · 6 entries
gpt-5.1-chatupdateca7a400Nov 2, 2026, 03:02 AM
capabilitiestool callyesstructured outputyesreasoningyesjson modeyes
descriptionHistorical specifications. - Reasoning - Chat Completions...
knowledge_cutoff2024-09-30
context_window128000
max_output_tokens16384
tagline- Reasoning - Chat Completions API.
tools["function_calling"]
gpt-5.1-chatupdate17bcfbfSep 11, 2026, 06:36 AM
description- Reasoning - Chat Completions API. - Responses API . - S...→Historical specifications. - Reasoning - Chat Completions...
gpt-5.1-chatupdate73d11c6May 18, 2026, 03:39 AM
description- Reasoning - Chat Completions API. - Responses API . - S...
knowledge_cutoff2024-09-30
context_window128000
max_output_tokens16384
tagline- Reasoning - Chat Completions API.
tools["function_calling"]
gpt-5.1-chatupdate6231fb5Apr 22, 2026, 02:50 AM
namegpt-5.1-chat→gpt-5.1-chat Preview
gpt-5.1-chatupdate2b100acMar 23, 2026, 05:30 AM
model_typechat
gpt-5.1-chatcreate7f5c66fMar 21, 2026, 05:16 AM